Background: The lack of physical activity and obesity causes mild chronic inflammation that is associated with increased plasma levels of inflammatory markers. Evidence suggests that physical activity can reduce inflammatory markers. Objectives: The purpose of this study was to determine the effects of eight weeks of aerobic training with two intensities on levels of tumor necrosis factor-alpha (TNF- ), interleukin-6 (IL-6), and insulin resistance in obese Wistar rats. Methods: Twenty-four Wistar male rats (fourteen weeks old and weighing 250 - 300 g, body mass index > 30 g/cm2) were used. After two weeks of familiarity with the laboratory environment, the animals were randomly divided into three groups: (1) high-intensity aerobic exercise (n = 8); (2) moderate-intensity aerobic exercise (n = 8), and control (n = 8). The rats in moderate and high-intensity aerobic exercise groups were performed an increasing training for eight weeks and five days a week and one session per day for 60 minutes running at different speeds on a rodent motor-driven treadmill. Data were analyzed by paired sample t-test and repeated measures (ANOVA) for the inter-group and intra-group comparison of the variance changes. Results: Significant differences were found in serum TNF- levels (P = 0.027 and F = 3.42), IL-6 levels (P = 0.043 and F = 2.99), and insulin resistance index (P = 0.008 and F = 4.69) between the moderate, high-intensity aerobic exercises, and control groups. The levels of TNF- concentration was significantly different between moderate-intensity and control group (P = 0.01) and between the highintensity and control groups (P = 0.01). The insulin resistance index in MI (P = 0.01) and HI (P = 0.01) groups significantly decreased compared to the control group. Conclusions: The results of the present study show that both types of moderate-intensity and high-intensity aerobic exercise lead to the reduction of TNF- , interleukin-6, and insulin resistance index compared to the control group. Further studies are needed to shed light on the effects of different types of exercise on such indices, especially the use of long-term training sessions.
